boullay's filter, etc. 5 
consideration of scrupulous nicety, not to disregard economy 
in our operations. 
The filter of Messrs. Boullay consists of a long tin hollow 
cylinder, slightly conical towards the inferior part, and funnel- 
shaped at the extremity, to admit of being inserted in the 
neck of a bottle, which serves to support it, and at the same 
time to receive the eliminated liquid. At the part C D, is 
placed a metallic diaphragm, pierced with holes, fitting in ac- 
curately, and provided with a handle; its interposition is de- 
signed to intercept the escape of the vegetable powder: at 
part A B, a similar sieve reposes upon a small rim, intended 
to scatter the liquid over the surface of the vegetable recipient. 
One 14 inches in length, from one extremity to the other, 
and 2§ inches in diameter at the base of the cone; one 14 by 
4, and one 17 by 6, are convenient sizes, according to the 
quantity you wish to operate upon. 
But it is not essentially necessary that you should be at the 
expense of getting these instruments made. Glass adapters, 
of which there are various sizes, answer the purpose very 
well. Some beaks of broken glass retorts fulfilled my wishes 
completely. The adapters are best for ether and other vola- 
